A. Field of the Invention
The present invention relates to an axial vane rotary device. More particularly, the present invention relates to a shear block and guide slot that are used to actuate the vane in an axial vane rotary device.
B. Problems in the Art
A typical axial vane rotary device of the prior art (e.g. U.S. Pat. No. 5,429,084) includes a stator with a cylindrical internal chamber having an annular outer wall and two side walls. Each side wall has an annular cam surface. A rotor is rotatably mounted within the chamber. The rotor has an annular outer wall and a plurality of singularly spaced apart, axially extending slots extending therethrough. A vane is slidably received in each slot. The vanes reciprocate axially and alternatively expand and compress spaces between adjacent vanes and the cam surfaces as the rotor rotates. The cam surfaces have alternating first portions and second portions. The second portions are further from the rotor than the first portions. The first portions of one cam surface are aligned with second portions of another cam surface at the opposite end of the device. The slots extend radially outwards on the rotor to the outer wall thereof. The outer end of each vane slidably engages the annular outer wall of the stator. The outer wall of the stator may have a guide cam and the vanes may have a follower received by the guide cam. The guide cam is shaped to cause the vanes to reciprocate axially with respect to the rotor as the rotor rotates. Each of the vanes may have resiliently biased first seals extending along the inner edge and second seals along side edges thereof.
The above prior art device utilizes a pin projecting from the vane, equipped with an anti-friction shoe, as the follower that is received by the guide cam. This arrangement functions adequately when the rotary device rotates at slow speeds and when the mass of the vane is relatively small. However, when the axial vane rotary device is operated at high speeds, or a vane of large mass is used, large shear forces develop which cause the pin, or the pin and shoe combination, to break. The breaking of the pin allows the vane to forcefully contact the annular walls of the stator, resulting in even greater damage to the axial vane rotary device. There is a need for a guide member that can withstand large shear forces without fracturing.
In addition, the guide slot in the above prior art device is machined into the inner surface of the stator. This is a difficult position in which to machine the slot. It is also difficult to repair the guide slot in the event of wear or other damage.
Therefore, it is a primary objective of the present invention to provide an improved guide member and guide slot that solve problems and deficiencies in the art.
It is a further object of the present invention to provide a shear block as a guide member that can withstand the large shear forces that are present when the axial vane rotary device is operated at high speeds or when the vane has a relatively large mass.
A still further object of the present invention is to provide a guide slot that reduces contact pressure on the guide member.
A still further object of the present invention is to provide a guide slot having members that are easy to remove and replace.
A still further object of the present invention is to provide a guide slot and shear block that are economical to manufacture and durable in use.
These and other objects will be apparent to those skilled in the art.